Loading Applet in a web browser

Hi guys, I really need help. I created an applet and its working fine if I use an appletviewer to open it, but if I try to open it in web browser it give error such as applet noninted and when i check for more details I see ClassNOTfound, then i tried moving the html file to the same folder as the .class file its refering to. Then I have another error: NoClassDefFound. SOS!:confused: